Explain whether or not a binomial distribution is a suitable model for the random variable.

(a) the number of tosses of a fair coin before the coin lands 'head'

(b) the score a pupil gets in answering 10 true/false questions with 1 mark for a correct answer and -1 for a wrong answer

(c) the number of rainy days in a randomly chosen week at a certain place for which weather records show that it rains on 40% of the days